Urinary tract infection (UTI) is one of the most commonly acquired bacterial infections in ambulatory and hospitalized populations and E.coli is the most common urinary pathogen, accounting for 90% of UTIs acquired in the community. Antimicrobial treatment and prophylaxis has resulted in increasing resistance to antimicrobials among uropathogenic bacteria both in the United States and worldwide. Several observational studies and a few randomized trials suggest that cranberry juice reduces the incidence of UTI. Reduced incidence of UTI could decrease antibiotic use and ultimately minimize prevalence of antibiotic resistance. Our overall goal is to determine the effect of cranberry on reducing the rate of recurrent UTI and duration of symptoms over antibiotics alone. We propose a randomized clinical trial of 600 college women presenting to the University Health Service with acute urinary tract infection. The study will have 3 arms and patients will be randomly assigned to taking 8 ounces of juice twice a day containing either 27% cranberry juice, 13.5% cranberry juice, or placebo juice. In addition, we will determine whether regularly taking cranberry juice changes the 3 and 6 month prevalence of bladder, rectal, vaginal and periurethral colonization with E coli containing known uropathogenic virulence factors relative to placebo controls. The results of this study will increase our understanding of the cranberry juice effect on reducing the symptoms of acute UTI, and on preventing recurring UTIs. We will be able to understand the dose-response effects on the outcomes of interest, including on side effects and compliance. We will also be able to evaluate if the bacterial population in the vagina, periurethra and stool is different after regularly drinking cranberry juice compared to placebo.